Read.me position switches provide a versatile and cost-effective means of monitoring piston position in a hydraulic cylinder. The switching signal which they generate can be used to control or sequence actions which correspond to specific points in a production cycle or process, as determined by the position of the cylinder's piston.
The Parker Read.me switch is a low profile external device, which can be used on conventional steel-bodied cylinders operating at full rated pressures. They are 'designed in' to the cylinder and must be specified at the time of order.
Accurate, reliable and versatile
Does not affect cylinder build length
Permits switching at any point, including end of stroke
Non-contacting design has no wearing parts
Quickly and easily positioned and adjusted
For use at full working pressure – no de-rating required
Low-profile design reduces risk of physical damage
A cost-effective alternative to transducers where simple position control is required
How Read.me Works
The Read.me switch allows piston position to be ‘read’ through a standard steel cylinder tube. It employs magnets attached to the piston in the cylinder, and an external switch which responds to changes in the polarity of a magnetic field. On first use, the cylinder tube is ‘formatted’ by completing a full stroke to establish residual magnetism. Once formatted, moving the piston with magnets through the cylinder creates a second, stronger field, opposite in polarity to the residual magnetism of the cylinder tube. As this field passes under the Read.me switch, the change in polarity of the magnetic field is detected and the switch is operated. The switch is fitted with two LEDs, to indicate when the piston is inside or outside the switching zone.
Switching output - PNP or NPN
Hysteresis* - 5mm
Repeatability* - 0.5mm
Load current - 100mA
Leakage current < 10μA
Voltage drop - < 1.5V DC
Short circuit and overload protection - Yes
Reverse polarity protection - Yes
Supply voltage - 10 – 30V DC
Current consumption - < 30mA
Operating temperature range - -25°C to +85°C
Enclosure rating - IP671
* Hysteresis and repeatability figures shown are based on measurements using a cylinder with outer diameter of 46mm, wall thickness of 3mm and piston speed of 0.5m/s.